Continuous monitoring of Rabi oscillations in a Bose-Einstein condensate

Minimally disruptive measurement techniques are a key tool for modern quantum science. In ultracold atomic systems, ancilla based methods or optical cavities are commonly used to realize weak measurements. In superconducting circuits, the macroscopic nature of the quantum mechanical degree of freedom enables direct dispersive monitoring of a qubit during its evolution. We implement an analogous off-resonant technique to directly and continuously monitor the evolving spin state of Raman-driven Bose-Einstein condensates trapped in arrays of optical tweezers, without the use of optical cavities or ancillae. We study the behavior of Rabi oscillations under different continuous measurement strengths and initial conditions. Continuous monitoring enables real-time feedback to an evolving quantum system; we report on progress in implementing such feedback for applications such as stabilization against decoherence, generation of squeezed states and other interactive quantum phenomena.